2009 INFINITI QX56 cooling

LOW-PRESSURE PIPEHA-37
< ON-VEHICLE REPAIR >
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LOW-PRESSURE PIPE
Removal and Installation for Low-Pressure PipeINFOID:0000000003775312
REMOVAL
1. Discharge the refrigerant. Refer to HA-20, "HFC-134a (R-134a) Service Procedure".
2. Remove the cowl top and the cowl top extension. Refer to EXT-18, "Removal and Installation"
.
3. Remove the low-pressure pipe. CAUTION:
Cap or wrap the joint of the pipes with suitable material such as viny l tape to avoid the entry of air.
INSTALLATION
Installation is in the reverse order of removal.
Refer to HA-29, "Component"
.
CAUTION:
 Replace the O-ring of the high/low-pressure pipe with a new one, then apply compressor oil to it
when installing it.
 After charging refrigerant, check for leaks.
Removal and Installation for Rear High- and Low-Pressure A/C and Heater Core Pipes
INFOID:0000000003775313
REMOVAL
1. Discharge the refrigerant from the A/C system. Refer to HA-20, "HFC-134a (R-134a) Service Procedure".
2. Drain the coolant from the engine cooling system. Refer to CO-11, "Changing Engine Coolant"
.
3. Disconnect the underfloor rear heater hoses (1 and 2) from the rear heater pipes underneath the vehicle.
 : Front
4. Remove the rear high- and low-pressure pipes bolt (A) to dis- connect the rear high- and low-pressure pipes from the under-
floor rear high- and low-pressu re pipes underneath the vehicle.
CAUTION:
Cap or wrap the joint of the pipes with suitable material
such as vinyl tape to avoid the entry of air.
5. Remove the rear high- and low-pressure pipes nuts (B).
NOTE:
The remaining steps are performed inside the rear luggage area of the vehicle.
6. Remove the luggage side finisher lower RH. Refer to INT-19, "Removal and Installation"
.
7. Disconnect the rear heater core hoses (1 and 2) from the rear heater core (3).
 : Front
ALIIA0216ZZ
ALIIA0218ZZ
Revision: December 20092009 QX56

HA-38
< ON-VEHICLE REPAIR >
LOW-PRESSURE PIPE
8. Remove the rear high- and low-pressure pipes bracket bolt (A)to release the bracket.
 Rear blower motor (1)
 : Front
9. Remove the rear high- and low-pressure pipes bolt (A) to dis- connect the rear high- and low-pressure pipes from the rear
expansion valve (1).
 : Front
CAUTION:
Cap or wrap the joint of the pipes with suitable material
such as vinyl tape to avoid the entry of air.
10. Disconnect the following electrical connectors:  Rear air mix door motor (1)
 Rear variable blower control (2)
 Rear blower motor (3)
 : Front
11. Disconnect the ducts from the rear heater and cooling unit assembly. Refer to HA-29, "Component"
.
12. Remove the rear heater and cooling unit assembly. CAUTION:
Cap or wrap the joint of the pipes with suitable material such as viny l tape to avoid the entry of air.
13. Remove the rear high- and low-pressure A/C pipes.
INSTALLATION
Installation is in the reverse order of removal.
Refer to HA-29, "Component"
.
CAUTION:
 Replace the O-rings on the rear high- and low-pr essure A/C pipes with a new ones, then apply com-
pressor oil to them for installation.
 After charging the refrigerant, check for leaks.
Removal and Installation for Underfloor Rear High- and Lo w-Pressure A/C and Heater
Core Pipes
INFOID:0000000003775314
REMOVAL
1. Drain the engine coolant. Refer to CO-11, "Changing Engine Coolant".
2. Disconnect the battery negative terminal.
3. Disconnect the generator harness.
4. Discharge the refrigerant. Refer to HA-20, "HFC-134a (R-134a) Service Procedure"
.
ALIIA0219ZZ
ALIIA0220ZZ
ALIIA0221ZZ
Revision: December 20092009 QX56

HIGH-PRESSURE PIPEHA-41
< ON-VEHICLE REPAIR >
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M A
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HIGH-PRESSURE PIPE
Removal and Installation for High-Pressure PipeINFOID:0000000003775316
REMOVAL
1. Remove the cowl top extension. Refer to EXT-18, "Removal and Installation".
2. Disconnect the battery negative termi nal and positive battery terminal.
3. Reposition the IPDM E/R aside.
4. Remove the front left wheel and tire assembly. Refer to MA-29, "Rotation"
.
5. Position aside the front floor insulator.
6. Discharge the refrigerant. Refer to HA-20, "HFC-134a (R-134a) Service Procedure"
.
7. Remove the low pressure pipe. Refer to HA-37, "Removal and Installation for Low-Pressure Pipe"
.
8. Remove the high-pressure pipe. CAUTION:
Cap or wrap the joint of the pipe with suitable mate rial such as vinyl tape to avoid the entry of air.
INSTALLATION
Installation is in the reverse order of removal.
Refer to HA-29, "Component"
.
CAUTION:
 Replace the O-ring of the high-pressure pipe with a new one, then apply compressor oil to it when
installing it.
 After charging refrigerant, check for leaks.
Removal and Installation for Rear High- and Low-Pressure A/C and Heater Core Pipes
INFOID:0000000003775317
REMOVAL
1. Discharge the refrigerant from the A/C system. Refer to HA-20, "HFC-134a (R-134a) Service Procedure".
2. Drain the coolant from the engine cooling system. Refer to CO-11, "Changing Engine Coolant"
.
3. Disconnect the underfloor rear heater hoses (1 and 2) from the rear heater pipes underneath the vehicle.
 : Front
4. Remove the rear high- and low-pressure pipes bolt (A) to dis- connect the rear high- and low-pressure pipes from the under-
floor rear high- and low-pressu re pipes underneath the vehicle.
CAUTION:
Cap or wrap the joint of the pipes with suitable material
such as vinyl tape to avoid the entry of air.
5. Remove the rear high- and low-pressure pipes nuts (B).
NOTE:
The remaining steps are performed inside the rear luggage area of the vehicle.
6. Remove the luggage side finisher lower RH. Refer to INT-19, "Removal and Installation"
.
7. Disconnect the rear heater core hoses (1 and 2) from the rear heater core (3).
 : Front
ALIIA0216ZZ
ALIIA0218ZZ
Revision: December 20092009 QX56

HA-42
< ON-VEHICLE REPAIR >
HIGH-PRESSURE PIPE
8. Remove the rear high- and low-pressure pipes bracket bolt (A)to release the bracket.
 Rear blower motor (1)
 : Front
9. Remove the rear high- and low-pressure pipes bolt (A) to dis- connect the rear high- and low-pressure pipes from the rear
expansion valve (1).
 : Front
CAUTION:
Cap or wrap the joint of the pipes with suitable material
such as vinyl tape to avoid the entry of air.
10. Disconnect the following electrical connectors:  Rear air mix door motor (1)
 Rear variable blower control (2)
 Rear blower motor (3)
 : Front
11. Disconnect the ducts from the rear heater and cooling unit assembly. Refer to HA-29, "Component"
.
12. Remove the rear heater and cooling unit assembly. CAUTION:
Cap or wrap the joint of the pipes with suitable material such as viny l tape to avoid the entry of air.
13. Remove the rear high- and low-pressure A/C pipes.
INSTALLATION
Installation is in the reverse order of removal.
Refer to HA-29, "Component"
.
CAUTION:
 Replace the O-rings on the rear high- and low-pr essure A/C pipes with a new ones, then apply com-
pressor oil to them for installation.
 After charging the refrigerant, check for leaks.
Removal and Installation for Underfloor Rear High- and Lo w-Pressure A/C and Heater
Core Pipes
INFOID:0000000003775318
REMOVAL
1. Drain the engine coolant. Refer to CO-11, "Changing Engine Coolant".
2. Disconnect the battery negative terminal.
3. Disconnect the generator harness.
4. Discharge the refrigerant. Refer to HA-20, "HFC-134a (R-134a) Service Procedure"
.
ALIIA0219ZZ
ALIIA0220ZZ
ALIIA0221ZZ
Revision: December 20092009 QX56

HAC-2
MAGNET CLUTCH ............................................72
System Description .............................................. ...72
Magnet Clutch Component Function Check ........ ...72
Magnet Clutch Diagnosis Procedure ................... ...73
WATER VALVE CIRCUIT ..................................77
Description ........................................................... ...77
Water Valve Diagnosis Procedure ..........................77
AMBIENT SENSOR ...........................................79
Component Description ....................................... ...79
Ambient Sensor Diagnosis Procedure ....................79
Ambient Sensor Component Inspection .................80
IN-VEHICLE SENSOR .......................................82
Component Description ....................................... ...82
In-Vehicle Sensor Diagnosis Procedure .................82
In-Vehicle Sensor Component Inspection ..............84
OPTICAL SENSOR ...........................................85
Component Description ..........................................85
Optical Sensor Diagnosis Procedure ......................85
INTAKE SENSOR ..............................................87
System Description .............................................. ...87
Intake Sensor Diagnosis Procedure .......................87
Intake Sensor Component Inspection ................. ...88
POWER SUPPLY AND GROUND CIRCUIT
FOR CONTROLLER ..........................................
89
Component Description ....................................... ...89
A/C Auto Amp. Component Function Check ..........89
A/C Auto Amp Power and Ground Diagnosis Pro-
cedure .....................................................................
90
ECU DIAGNOSIS .......................................91
AIR CONDITIONER CONTROL ..................... ...91
A/C Auto Amp. Terminals Reference Values ..........91
Wiring Diagram .................................................... ...93
SYMPTOM DIAGNOSIS ...........................109
AIR CONDITIONER CONTROL ..................... ..109
Symptom Matrix Chart ........................................ .109
INSUFFICIENT COOLING ................................110
Component Function Check ................................ .110
Diagnostic Work Flow ...........................................111
Performance Chart ................................................113
Trouble Diagnoses for Abnormal Pressure ...........114
INSUFFICIENT HEATING ................................118
Component Function Check .................................118
NOISE ...............................................................120
Component Function Check ................................ .120
MEMORY FUNCTION DOES NOT OPERATE ..122
Memory Function Check ...................................... .122
PRECAUTION ...........................................123
PRECAUTIONS .............................................. ..123
Precaution for Supplemental Restraint System
(SRS) "AIR BAG" and "SEAT BELT PRE-TEN-
SIONER" .............................................................. .
123
Working with HFC-134a (R-134a) ........................ .123
Precaution for Service Equipment ........................124
Revision: December 20092009 QX56

HAC-10
< FUNCTION DIAGNOSIS >[AUTOMATIC AIR CONDITIONER]
FUNCTION INFORMATION
Defroster door motor is malfunctioning. Go to Trouble Diagnosis Procedure for Defroster Door Motor.
HAC-46
Front blower motor operation is malfunction-
ing.Go to Trouble Diagnosis Procedure for Front Blower Motor.
HAC-51
Rear blower motor operation is malfunction-
ing.Go to Trouble Diagnosis Procedure for Rear Blower Motor.
HAC-57
Rear air discharge outlet does not change. Go to Trouble Diagnosis Procedure for Mode Door Motor (rear). HAC-62
Rear air temperature does not change. Go to Trouble Diagnosis Procedure for Air Mix Door Motor (rear).HAC-62
Magnet clutch does not engage.Go to Trouble Diagnosis Procedure for Magnet Clutch. HAC-72
Insufficient coolingGo to Trouble Diagnosis Procedure for Insufficient Cooling. HAC-110
Insufficient heatingGo to Trouble Diagnosis Procedure for Insufficient Heating. HAC-118
NoiseGo to Trouble Diagnosis Procedure for Noise. HAC-120
Self-diagnosis cannot be performed. Go to Trouble Diagnosis Procedure for Self-diagnosis. HAC-89
Memory function does not operate.Go to Trouble Diagnosis Procedure for Memory Function. HAC-122
SymptomReference Page
Revision: December 20092009 QX56

HAC-26
< COMPONENT DIAGNOSIS >[AUTOMATIC AIR CONDITIONER]
MODE DOOR MOTOR
The mode door motor (front) is attached to the heater & cooling unit
assembly. It rotates so that air is discharged from the outlet as indi-
cated by the A/C auto amp. Motor rotation is conveyed to a link
which activates the mode door.
Mode Door Motor (Front)
Component Function CheckINFOID:0000000003775344
INSPECTION FLOW
1.CONFIRM SYMPTOM BY PERFORMING OP ERATIONAL CHECK - DISCHARGE AIR
1. Press mode switch four times and then press the (DEF) switch. Each position indicator should change shape (on display).
2. Confirm that discharge air comes out according to the air distribution table. Refer to HAC-16, "
Discharge
Air Flow (Front)".
NOTE:
Confirm that the compressor clutch is engaged (visual inspection) and intake door position is at FRESH
when DEF ( ) or D/F ( ) is selected.
Can a symptom be duplicated?
YES >> GO TO 3.
NO >> GO TO 2.
2.PERFORM COMPLETE OPERATIONAL CHECK
Perform a complete operational check and check for any symptoms. Refer to HAC-4, "
Operational Check
(Front)".
Can a symptom be duplicated?
YES >> Refer to HAC-3, "How to Perform Trouble Diagnosis For Quick And Accurate Repair".
NO >> System OK.
3.CHECK FOR SERVICE BULLETINS
Check for any service bulletins.
>> GO TO 4.
4.CHECK MODE DOOR OPERATION
Check and verify mode door mechanism for smooth operation in each mode.
Is the inspection result normal?
YES >> GO TO 5.
NO >> Repair as necessary.
5.PERFORM A/C AUTO AMP. SELF-DIAGNOSIS
Perform self-diagnosis to check for any codes. Refer to HAC-23, "
A/C Auto Amp. Self-Diagnosis".
Are any self-diagnosis codes present?
YES >> Refer to HAC-24, "A/C System Self-Diagnosis Code Chart".
NO >> GO TO 6.
6.PERFORM A/C AND AV SWITCH ASSEMBLY SELF-DIAGNOSIS
Perform self-diagnosis to check the A/C and AV switch assembly. Refer to HAC-23, "
A/C and AV Switch
Assembly Self-Diagnosis".
Is the inspection result normal?
YES >> Replace A/C and AV switch assembly. Refer to VTL-7, "Removal and Installation".
NO >> GO TO 7.
WJIA0587E
Revision: December 20092009 QX56

HAC-32
< COMPONENT DIAGNOSIS >[AUTOMATIC AIR CONDITIONER]
AIR MIX DOOR MOTOR
Air Mix Door Control Specification
COMPONENT DESCRIPTION
Air Mix Door Motors (front)
The driver (1) and passenger (2) air mix door motors are attached to
the front heater & cooling unit assembly. These motors rotate so that
the air mix door is opened or closed to a position set by the A/C auto
amp. Motor rotation is then conveyed through a shaft and the air mix
door position is then fed back to t
he A/C auto amp. by the PBR built
into the air mix door motors.
Air Mix Door Motor (rear)
The air mix door motor (rear) (1) is attached to the rear heater &
cooling unit assembly. These motors rotate so that the air mix door is
opened or closed to a position set by the front (or rear) air control.
Motor rotation is then conveyed through a shaft and the air mix door
position is then fed back to the A/ C auto amp. by the PBR built into
the air mix door motors.
Air Mix Door Motor Component Function CheckINFOID:0000000003775347
INSPECTION FLOW
1.CONFIRM SYMPTOM BY PERFORMING OPER ATIONAL CHECK - TEMPERATURE INCREASE
1. Turn the temperature control dial (driver) clockwise until 32 °C (90° F) is displayed.
2. Check for hot air at discharge air outlets.
>> GO TO 2.
2.CONFIRM SYMPTOM BY PERFORMING OPER ATIONAL CHECK - TEMPERATURE DECREASE
1. Turn the temperature control dial (driver) counterclockwise until 18 °C (60 °F) is displayed.
2. Check for cold air at discharge air outlets.
Can a symptom be duplicated?
YES >> GO TO 4.
NO >> GO TO 3.
3.PERFORM COMPLETE OPERATIONAL CHECK
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Revision: December 20092009 QX56